Switch mechanism



Feb. 19, J G, SWITCH MECHANISM Filed July 26, 1954 F l G. 6 0w IN V EN TOR.

JOHN G. SMITH ATTORNEY United States Paten 3 SWITCH 'MECHANISM John GJSmith, Philadelphia, Pa., assignor to Burroughs This invention rel ates to switch :me'chanis'ms and particularly' to an improved switch especially adaptable for use in cornputers andthe like. 1

In the an er *elec'tric switches, and especially those designed' fo'r "high speed use in. computingequipment, the disadvantages of the commercially available switches are their large size,*short= mechanical life and contact reaction or bounce. In the open construction of such-lswitches theyare subjectto ingressof dust and foreign material and the possibility of short 'cireuiting. 'In the enclosed type of suchswitches they 'have been largely of the snap action type which at' high speeds -an'd with any degree of J overthrow are sh'o'rt lived.

-An= important-object ofthe present invention is to provide a switch 'rnechanism=which is-especially desirable for use in computers and-the like and which is reliable in operation at highfispee'ds and lies along mechanical and electrical life.

i l-nether important= object of the invention is *to provide a-switch mechanism in which-relatively high contact pressures 'are utilized to actuate amovable switchingmember btit=without loading the "switching member, thus'enabli'ng theoperation oftheme'chanis'm at high speeds andwithout-contact bounce.

iAnother import-antobject=of the invention is to provide-a'ba'sic s'witchstructurewhich is readilyconver'tible in -thejriro'ce'ss of fabrication to'one of'seve'rabfi'ni'shed designs by the simple substitution of parts.

A still "further important object of'the invention is to provide an improved switch mechanism which has .its parts designed in a novel-manner "for assembly into a small compact enclosed "switch for operation at high speeds Without contact reaction or bounce andwhich is designed for stacking with similar -switchmechanisms in a multiple switch assembly 'for'us'e in confined spaces of computing machine's.

-Various other objects, advantages .andmeritorious .fea tures of the invention will becomemorefully apparent from the followingspecification, appended claims and accompanying drawings wherein:

Fig. '1 is a top'plan view of a switch mechanism illustrating'one embodiment of the'invention and with the cover member removed to expose the interior thereof;

Fig. 2'is 'a 'similarview as Fig. l but showing a modified form of switch structureprovided by the substitution and rearrangement "of certain of the parts thereof;

Fig. 3 is an edge view'of the switch structure of Fig. '1 partly broken away'in section;

Figs. 4 and 5 are fragmentary views'ofthe contact'area inthe switch-mechanism of Fig. "1 illustrating successive positions of the operatin'g'parts in the actuation of the switch;

Fig.6 is a plan view similar-to Figs. '1 and 2, illustrating anot'her form of switch structure emb'o'dying'the inventi'om 'and :Fig. 7-is a perspective view illustrating a stack ofsimilar switches each constructed in accordance with 'the invention and predisposed for operation by a series of 2,782,287 Patented Feb. 1 l 7 machine.

Referring now to the embodiment of the invention illustrated in Figs. 1 and 3, there is illustrated a small, compact switch for use in computing machines,'the operating parts of which are enclosed and sealed from the accumulation of dust and other foreign matter. The bodyof the-structure illustratedin Figs. 1 and 3 is composed of amain body section 10 and a subsidiary bodysection 12, thelatter'serving as acover for the switch body. The two body sections are formed of electrical insulating material suchas a phenolic type'of plastic. 'The'main body section, as shown in Fig. l, is formed'at the'tim'e it is molded with connecting cut-away areasopening'out through one nae-er the "section, the sidewalls oftliese cut-away areasextentling'generally'vertically to" the plane of the' body's'ectionand serving as supporting. surfaces for severalof the'relatively fixed operatingrnembers'of *the switch. "The cover section 12 overlies the side of "the body section 10 through whichthese cut-away portionso'pen and thus seals the same fromthe ingress of dust and other foreign matter.

Theop'era'tingmembers of the switchof Fig. 1 include a --pairof'1'elatively stationary contact terminals or members I4 and f6 which h'ave i'nternal portions extending generallyparallel to one another in opposed confronting relation. Carried on these internalparallel portions of the terminal "members 1' 5 and '16 are projecting contact points-orbuttons 18 and ZtTrespec'tiVeIy. These'bu'ttons are preferably in line'with one another, as illustrated in Fig. l. The contactme'mbers 14 and lra are sho'wn as beingdn the form of Inetallicstrips preferably formed "ofbr-ass and their'opp'osite end sections remote from the contact'buttonsar'e arranged 'tojpass through a side edge of the switchbody. "The projecting end sections of the terminal members 14 and are indicated at 22 and 24- respectively. 'The contact. points or buttons may be: formed of any suitable'materials, such as silver, tungsten.

or p'alladium-silver alloy, and secured to the terminal membersin -any suitableway, as brazing or riveting.

lnterposedbetween'the fixed terminal members 14 and 16 and supported forjrnovement in the space between the contact'buttons 18 and His a movable switching member 26 which is in the form of a flat-blade or arm extending generally parallel to the inner end sections of the terminal members. The arm 26 carriesa contact point or button 28 on one si'dethereof and another contact point or but ton on the other side thereof which are capable of engaging the contact buttons 18 and 21 respectively of the terminal'mernbers at separate times. The arm 26 is mounted on *a'flexible metallic strip 32 which is curved intermediate its ends to provide a U-shaped bend 34. The strip 32 maybe formed of Phosphor-bronze material. The arm or'blade 26 ismounted on one'end section of the flexible member32. The opposite end section of the flexible member is attached by spot Welding or otherwise to a stationary terminal member36 which, like the terminal members 22 an'd24, has an extension 38 projecting from the switch body. Preferably, as shown, the three external'ter minal end sections 22, 24 and 33 extend from the same edge of 'theswitch body and generally parallel to one another. Normally, without any pressure being imposedupon the blade or arm 26 of the switchingmember,'the blade lies in a plane half way between thecontact buttons 18 and 20 of theterminal members and thusv its own contact buttons 28Iand 30 would be out of contact therewith. Because 'of the springiness of the flexible strip 34, the arm 26 is capable of swinging in the area between thecontact'butt'ons 18 and 20 to engage one or theother thereof. It is also evident from Fig. .1 that the blade or arm 26 has an end extension 40 projecting be yond the working area of the contact buttons and beyond 3 the terminating edge of the fixed terminal member 14.

The switching member 26 is moved from one to the other of its two contact positions by means of an actuator or operating finger generally indicated at 42 and lying in a plane between the opposite sides of the switch body. The operating finger 42 has an overall or general shaped configuration and lies within a recess formed in the main body section 10 which opens out through an edge of the body differing from that from which the outer terminal ends of the members 22, 24 and 38 project. The greater portion of the finger 42 lies within the recess and thus within the outer confines of the body, but the finger is provided with a rise or hump 44 which projects out of the recess in which the finger is located and beyond the outside of the switch body for engagement by an external operating force.

As previously mentioned, the finger 42 is of a general C-shaped formation. One end of the finger is pivoted in the body by means of a small rivet or pin 46 which, as shown in Fig. 3, may also serve to secure the cover section 12 to the main body section 10. As is evident in Fig. 1, the pivoted axis for the finger is located adjacent to one corner of the body and at a relatively remote distance from the operating area of the contact buttons. From the pivot axis the finger has a relatively straight body portion 48 which extends alongside of and generally parallel to the inner end section of the stationary terminal member 14. Beyond this portion 48 the finger is bent at approximately 90 to provide a portion 50 which extends toward the opposite terminal member 16 and close to the working area of the contact buttons. The extremity of the finger portion 50 is inturned to form a step or lip 52 extending toward the operating area of the buttons and shaped to engage the side of the switching arm 26 opposite to the terminal member 14. It is evident from Fig. 1 the C shape configuration of the finger is such that if a straight line is drawn from the pivot end of the finger to the lip end 52 it will pass generally through the working area of the contact buttons.

Interposed between the finger portion 48 and the fixed terminal member 14 is a coiled wire spring 54, the tension of which is so designed as to yieldingly urge the finger away from the terminal member. A second coiled wire spring 56 is provided which is interposed between the finger portion 48 and the free end 40 of the switching member 26. The two springs 54 and 56 are spaced apart and arranged with their axes in generally parallel relation to one another. The first coiled spring 54 exerts a pressure to move the finger 42 away from the stationary terminal member 14 and in so doing brings the lip 52 of the finger into engagement with the free end of the switching blade 26 and carries the same therewith bringing the contact points or buttons 28 and 18 into contact with one another to close an electrical connection therebetween. The second coil spring 56 bodily moves along with this movement of the blade and finger. Thus Fig. 1 illustrates the normal operating position of the parts with the switching member 26 in electrical contact with the stationary terminal 14.

When the finger 42 is moved inwardly of the body and against the resistance of the coil spring 54, it operates through the second spring 56 and exerts pressure on the extension 40 of the switching member urging the latter in the same direction of the movement of the finger and toward the opposite stationary terminal member 16. The lip 52 moves with the finger thus freeing the switching member for this movement. Figs. 4 and 5 illustrate progressive positions of the operating members of the switch when the finger is actuated in this direction. In Fig. 4 the finger has been partially depressed into the body sufiicient to move the switching member so that the contact point or button 30 thereof is in engagement with the button 20 of the fixed terminal member 16 thereby making an electrical connection therewith. Fig. 5 illustrates the final position of the parts after the finger has been fully depressed. It is evident from Fig. 5 that the finger has an overthrow position in which the lip 52 is moved away from the end 40 of the switching member while the force applying spring 56 is further compressed.

It is evident that during the operation of the mechanism from one switching position to the other that a high contact pressure is obtained in either switching position without loading or applying other than only an extremely mild force upon the leaf spring element 32. The helical coil springs 54 and 56 do this work, thus preserving the leaf spring for long mechanical life. When the external force applied on the finger is removed, the first coil spring 54 returns the operating parts to the normal position shown in Fig. 1.

Fig. 2 illustrates a modification of the invention wherein the basic structure is preserved where differently designed parts having the same function are substituted for certain of the parts shown in the embodiment of Fig. 1. In Fig. 2 the finger identified at 42', for example, is generally like that previously described except that the external knob for actuating the finger has been changed in shape and is located at the juncture of the portions 48' and 50' for projection from one corner of the switch body. The fixed terminal members also have been modified so that they project from another edge of the switch body. As shown in Fig. 2, new terminal members 14 and 16' have been substituted which are generally like those described in connection with Fig. 1 but have terminal extensions 22 and 24', respectively, which are shaped so as to extend through an edge of the switch body closer to the pivotal axis of the finger. Likewise, a terminal member 36' has been substituted for the similarly numbered element in Fig. 1 and arranged so that it has its terminal extension 38 projecting from the same edge as the terminal ends 22' and 24'.

In order to provide optional location of the terminal extensions from one or the other edge of the same switch body, the main body section 10 is provided during its fabrication with weak wall portions identified at 58, 60 and 62 of Fig. 1, and at 64, 66 and 68 of Fig. 2. These weak wall portions are frangible and can be broken through when the switch is assembled and depending upon the selection of the terminal members they will be extended from the switch body either as shown in Fig. 1 or in Fig. 2. It is obvious that other modifications of the switch body and operating parts may be made in order to vary the application of the switch mechanism.

The two body portions 10 and 12 are secured together by rivets or other suitable connecting means. One of these rivets has already been identified at 46 as the pivotal axis for the actuator 42. Another rivet is indicated at 70 adjacent to the opposite corner of the body. The switch body is also provided with one or more holes extending completely through from one side to the other side thereof. In the illustrated embodiments of the invention both the main body portion and the cover portion are provided with two registering holes identified at 74 and 76. These holes may serve to receive rods or other supporting elements upon which one or more of these switch bodies are mounted.

Fig. 6 illustrates a modification of the invention wherein the two terminal members and the contact member are formed of relatively thicker metallic material and terminate completely within the body. The two terminal members are identified at 78 and 80 and the contact member at 82. The contact member is secured as in the manner previously described to a flexible strip 84 which in turn has its opposite end secured to another metallic member 86 within the body. Extending through one edge of the switch body are circular holes in which are received sleeve-like conducting elements 88. (Due conducting element is associated with each of the two terminal members and the member 86 and is connected thereto. These sleeve elements serve as sockets for the reception of external terminals to provide an electrical connection.

In Fig. 7 there is illustrated a plurality of the switch mechanisms, such as the type illustrated inFigs. 1 and3,

mounted in a row and compactly rassembled together into a stack. The actuating members of these switch mechanisms are all arranged to projectfrom one side of the stack in juxtaposition to a series of rotary cams 90 mounted on a common operating shaft 92. Since each switch mechanism has flat parallel sides they may be mounted'insuch close side-by-side relation. In actual practice the switch mechanism embodying the invention is quite small, and may be an inch square or less in its major plane and one quarter of an inch thick or less.

What I claim is: v

1. A switch structure comprising two relatively fixed, spaced apart and confronting contact members; a contact arm mounted for movement between the two contact members and operable upon movement to engage one or the other contact member; an actuating finger for controlling the movement of the arm and swingably mounted for movement in the plane of movement of the arm; a pair of coil springs; one of said springs being interposed between the finger and one of the contact members; the other of said springs being interposed between the finger and the movable arm; the first spring being under such tension as to urge the finger away from the contact member; the second spring acting as the operating connection between the finger and the movable arm and operable to move the arm into engagement with one of said contact members and thereafter yieldingly compress as further movement of the finger in the same direction is absorbed thereby; and means carried by the finger engageable with the side of the arm opposite to the direction in which the finger is urged to thereby draw the arm in the direction of movement of the finger and into engagement with the other of said contact members when the finger is moved by the first spring.

2. In combination with a switch having a pair of relatively fixed, spaced apart confronting terminal members and a movable contact arm interposed between the terminal members and capable of engagement with one or the other of the terminal members at different times, an operating finger mounted for swinging movement in the plane of movement of the contact arm and exhibiting generally the configuration of the letter 0, means pivoting one end of the finger about a fixed axis and such that the finger extends alongside of one of the terminal members in spaced relation thereto and has its opposite free end in position to engage the contact arm on the side thereof opposite to the terminal member alongside of which the finger extends, a coil spring interposed between the finger and the terminal member along the side of which it extends and normally yieldingly urging the finger away therefrom, the free end of the finger serving to engage and move the arm in the same direction as the finger when the latter is moved by the spring, a second coil spring interposed between the finger and the contact arm and seated against the latter on the side thereof opposite to the side engaged by the free end of the finger, said second spring serving as the operating connection between the finger and the arm to move the latter in the same direction as the finger when the same is moved against the resistance of the first spring.

3. A switch mechanism comprising, in combination, a pair of relatively fixed terminal members predisposed in spaced apart confronting relation and each provided with a contact button facing toward the other, a contact arm supportingly positioned at one end for movement between the fixed terminal members and provided with a contact button on each side thereof aligning with the button of the terminal member on the same side thereof for engagement therewith when the arm is moved in that direction, the opposite end of the arm projecting beyond the contact buttons and terminating freely, an operating finger of generally C shaped configuration, means pivotally connecting one end of the finger on the side of the contact buttons opposite to thetfree end of the arm, the finger being mounted such that it extends around one of the terminal members and'has its opposite end'free and disposed on the side of the arm opposite to said last mentioned terminal member, a pair of coiled springs each seated at one end on the finger and extending generally parallel with one another, one of said springs having its opposite end seated on the terminal member around which the finger extends, the other of said springs having its opposite end seated on the free end of the arm on the side thereof opposite to that engageable by the free end of the'finger, the disposition of the first spring being such that it yieldingly urges the finger away from the terminal members and thereby causes the free end of the finger to engage and move the arm therewith, the disposition of the second spring being such it serves as a yielding force transmitting medium between the finger and the arm when the former is moved against the resistance of the first spring.

4. A switch mechanism comprising, in combination, a body of electrical insulating material having a relatively fiat generally rectangular configuration and being provided with cut out portions in the body opening out through one side thereof, a pair of spaced terminal members positioned in separate cut out portions of the body and disposed in relatively fixed spaced apart confronting relation to one another, a -spring leaf contact member positioned in another cut out portion of the body and extending between the two terminal members and capable of movement into engagement with one or the other, said body being further provided with a recess therein opening through one edge of the body, an operating finger for controlling the contact member positioned in the recess and having an actuating projection extending outwardly beyond said edge of the body, means mounting said finger for swingable movement in the recess and in the direction toward and away from the members, a pair of coil springs in the body, one of said springs being interposed between the finger and one of the terminal members and acting to yieldingly urge the finger in the direction of its movement away from the terminal members, the other of said springs being interposed between the finger and the contact member and serving as the sole connection therebetween when the finger is moved in the direction of its movement toward the terminal members, an extension of the finger engageable with the side of the contact member opposite to the direction in which the finger is spring urged and operable when the finger is moved in that direction to engage and move the contact member in the same direction, and a separate conducting lead for each of said members extending through another edge of the body for electrical connection with circuitry external to the body.

5. A switch comprising, in combination, a body of electrical insulating material having a relatively thin fiat generally rectangular configuration, a spring leaf contact member in the body having one end relatively fixed against movement while the opposite end is free to move in the direction of the plane of the body, an electrical terminal member in the body and positioned in relatively fixed condition on one side of the contact member and in confronting relation to the free end thereof, said body having a recess therein on the side of the contact member opposite to the terminal member and opening out through an adjacent edge of the body, an operating finger for controlling the contact member positioned in the recess and having an actuating projection extending outwardly beyond said edge of the body, means mounting said finger in the body for movement in the direction of the plane of the body and toward and away from the contact and terminal members, spring means in the body engaging the operating finger and yieldingly urging the same outwardly away from the contact and terminal members, a coil spring seated at one end on the operating finger and at the other end on the free end of the contact member and serving as the sole operating connection therebetween when force is applied to the finger to move the same inwardly toward the contact and terminal members, said coil spring acting when the operating finger is moved inwardly to likewise move the free end of the contact member into engagement with the terminal member and thereafter to yieldingly compress its convolutions as it absorbs continued movement of the finger in the same direction, a hook-shaped extension on the operating finger engageable with the side of the free end of the contact member opposite to the direction in which the operating finger is urged by said spring means and operable when the finger is moved in that direction 53 to engage and move the contact member in the same direction to thereby disengage the contact member from the terminal member, and a separate conducting lead for the contact and terminal members extending through another edge of the body for electrical connection with the circuitry external to the body.

References Cited in the file of this patent UNITED STATES PATENTS 

